chore(docs): rename @private to @internal

The latter is understood by TypeScript's --stripInternal option, so this lets us
rely more on the tooling provided by typescript team.

modules/angular2/src/core/change_detection/change_detector_ref.ts

@@ -6,7 +6,7 @@ import {ChangeDetectionStrategy} from './constants';
  */
 export class ChangeDetectorRef {
   /**
-   * @private
+   * @internal
    */
   constructor(private _cd: ChangeDetector) {}
 

modules/angular2/src/core/change_detection/parser/locals.ts

@@ -3,7 +3,7 @@ import {BaseException} from 'angular2/src/core/facade/exceptions';
 import {ListWrapper, MapWrapper} from 'angular2/src/core/facade/collection';
 
 /**
- * @private
+ * @internal
  */
 export class Locals {
   constructor(public parent: Locals, public current: Map<any, any>) {}